The Stumble Pre-warning Of Prosthesis And Protection Strategy Analysis For Lower Limb Amputees

With the development of the powered knee joint prosthesis,the identification of typical terrain conditions and movement control can achieve the normal walking of patients.However,the safety of prosthesis is the basic guarantee to realize its function.The amputee inevitably falls down in the process of walking.So it is very important to study the stumble pre-warning and protection strategy of lower limb prosthesis.This thesis contains three sections: data acquisition and processing,the stumble pre-warning research,protection strategy analysis.The rapid detection of prosthesis stumble was realized and the motion control of the knee joint was studied.So it improved the walking security of the prosthesis users.First of all,a good data source is the basis to realize the pre-warning effect.This paper divided stumble into two major cases of tripping and slipping.The acceleration data and angle data were extracted and filtered from the sensitive reaction part of the body.Then combined with the human movement characteristics,the effective data source for the pre-warning of prosthesis stumble was obtained.Secondly,because of the walking mode and the response to the stumble were different between the long time prosthesis user and the initial stage patient.Therefore,this paper applied support vector machine and correlation analysis of two kinds of algorithms to design pre-warning system for two types of patients.The support vector machine was applied to the long time prosthesis user,and it combined the gray prediction theory for data extension to reduce the detection time.The correlation analysis was applied to the initial stage patient,and it combined the fuzzy adaptive variable weight algorithm with feedback regulation unit to improve the accuracy of pre-warning.Finally,MSP430f149 microcontroller was used to design the mobile portable pre-warning device.And the pre-warning system was preliminarily verified.In addition,this paper analyzed the protection strategy for the powered knee joint prosthesis during possible stumble,and provided a theoretical basis for the amputees to avoid fall as well as healthy people.